What results from a functional PAB regarding the normal pacemaker?

What results from a functional PAB regarding the normal pacemaker?

• A. It enhances the SA node function
• B. It can confuse the conduction pathways
• C. It takes over the pacing responsibility
• D. It completely resets the heart rhythm

Answer: (C)

A functional pacemaker activity takes over the pacing responsibility when the normal pacemaker, which is primarily the sinoatrial (SA) node, is not able to generate an adequate pace due to various reasons like disease or failure. In cases where the SA node is dysfunctional, alternative pacemaker sites (such as the atrioventricular (AV) node or purkinje fibers) can initiate impulses at their inherent rates, effectively assuming the role of the primary pacemaker. This ensures that electrical activity still occurs in the heart, allowing it to contract and maintain some level of cardiac output, even if it's not at the normal rate determined by the SA node.

The other options do not accurately describe the outcomes of a functional pacemaker. For instance, while enhancing SA node function might be beneficial, a functional pacemaker does not improve the SA node; instead, it compensates for its failure. Confusion in conduction pathways might occur due to various factors but is not a primary role or direct result of a functional pacemaker. Finally, the idea of completely resetting the heart rhythm does not align with the role of a functional pacemaker, which instead works to maintain pacing within the constraints of existing cardiac conduction.